1. Field of the Invention
This invention pertains to ball bats used, for example, in baseball and softball. More particularly, this invention pertains to tubular ball bats made of metal, such as aluminum.
2. Description of the Related Art
Recent years have seen an emergence of tubular, metal ball bats for use in ball sports, such as softball and baseball. Some of the tubular bats have objects located in the hollow core to improve various aspects of bat performance. Some manufacturers place rebound cores in the bats such as those shown in U.S. Pat. No. 5,511,777. This patent discloses a rebound core that is mounted in a tubular bat in order to dampen the sound and vibration caused by the impact between the bat and ball.
Other manufacturers place inserts in the bat to improve batting performance. See U.S. Pat. No. 5,415,398. This patent discloses an insert in the shape of a tubular sleeve that is mounted inside the tubular frame, within the impact portion of the bat. The sleeve is fixedly coupled at its distal ends to the bat, while its mid-portion is slightly separated radially from the surrounding impact portion of the bat.
While the sleeve insert of the '398 patent has been shown to improve hitting capacity, it is desired to improve the manufacturability of the bat so that the design is easier to manufacture, has better quality control, and other improved characteristics.